She was Thunderclan's medicine cat until a badger had killed her.
She went off to the moorlands beyond Windclan territory but returned later when Midnight the badger warned her that Thunderclan was in danger.
In what book?
Yes, Leafpool left her position as a warrior in ThunderClan when it was revealed she had been secretly meeting with Crowfeather from WindClan. She later returns to the Clan as a medicine cat after realizing her heart truly lies with ThunderClan.
Midnight is a wise badger that speaks cat. She knows a lot about StarClan and warned the cats about the Twolegs destroying the forest. She also warned Leafpool about the badger attack from her kin. That's what made Leafpool and Crowfeather go back. Then Midnight told WindClan to go help ThunderClan.
GoldenFlower died between Sunset and The Sight(Possibly of old age), her death was never mentioned in the books. She didn't die during the journey to the lake because she was still alive when the badger attack happened which was when ThunderClan was settled in their new lake territory.
A cheetah could rip a badger to shreds, but maybe not eat it. Even if the badger starts winning, the cheetah could run away.
Cinderpelt dies from a badger attack.
Luther Badger died in 1869.
Joseph Badger died in 1765.
Bert Badger died in 1965.
Rodney Badger died in 1853.